The present invention relates to a scroll compressor, and more particularly, it relates to a scroll compressor reducing pulsation caused when discharging a compressed high-pressure fluid.
As an example of a conventional scroll compressor, an in-shaft discharge type scroll compressor discharging compressed high-pressure refrigerant gas into a casing through a passage provided in a drive shaft driving the compressor is now described.
As shown in FIG. 4, a partition 125 separates a closed casing 101 into a suction chamber 123 and a discharge chamber 122.
The suction chamber 123 is provided therein with a scroll compression mechanism 103 for sucking and compressing refrigerant gas.
The scroll compression mechanism 103 is formed by a fixed scroll 110 and a movable scroll 111. Spiral fixed scroll teeth 110b project from an end plate 110a of the fixed scroll 110. Spiral movable scroll teeth 111b project from an end plate 111a of the movable scroll 111. The movable scroll teeth 111b fit with the fixed scroll teeth 110b thereby forming a compression chamber 114.
A suction port 110c is provided on a side surface of the fixed scroll 110 for feeding low-pressure refrigerant gas received from a suction pipe 105 into the compression chamber 114. A discharge port 111c is provided on a portion around the center of the end plate 111a of the movable scroll 111 for discharging the refrigerant gas compressed to a high-pressure state.
The discharge chamber 122 stores a motor 107. The scroll compression mechanism 103 is driven through a crank part 130 provided on the upper end of a drive shaft 108 of the motor 107. The drive shaft 108 is provided with a discharged gas passage 108e for guiding the refrigerant gas discharged from the discharge port 111c to a discharged gas outlet 108f provided on the lower end of the drive shaft 108.
The suction pipe 105 for feeding the refrigerant gas into the scroll compression mechanism 103 is connected to a portion of the casing 101 closer to the suction chamber 123. A discharge pipe 106 for discharging the high-pressure refrigerant gas from the casing 101 is connected to a portion of the casing 101 closer to the discharge chamber 122.
Operation of the aforementioned scroll compressor is now described.
Rotation of the motor 107 is transmitted to the scroll compression mechanism 103 through the drive shaft 108 and the crank part 130. Thus, the movable scroll 111 revolves with respect to the fixed scroll 110. The compression chamber 114 formed by the movable scroll teeth 111b and the fixed scroll teeth 110b contractedly moves from the outer peripheral portion toward the central potion due to the revolution of the movable scroll 111.
Thus, the low-pressure refrigerant gas fed from the suction pipe 105 into the compression chamber 114 through the suction port 110c is compressed to a high-pressure state and discharged from the discharge port 111c of the movable scroll 111.
The high-pressure refrigerant gas discharged from the discharge port 111c passes through the discharged gas passage 108e provided on the drive shaft 108 and flows out into the discharge chamber 122 from the discharged gas outlet 108f. The high-pressure refrigerant gas flowing out into the discharge chamber 122 passes through a clearance between the motor 107 and the casing 101 or the like and is delivered from the casing 101 through the discharge pipe 106.
However, the aforementioned scroll compressor has the following problems:
The compression chamber 114 formed by the movable scroll teeth 111b and the fixed scroll teeth 110b spirally moves from the outer peripheral portion toward the central portion following revolution of the movable scroll 111. At this time, the refrigerant gas compressed in the compression chamber 114 is discharged from the discharge port 111c, whereafter the refrigerant gas compressed in a next compression chamber is discharged.
The scroll compression mechanism 103 intermittently performs such discharge along with revolution of the movable scroll 111, and hence it follows that the discharged refrigerant gas pulsates. The pulsating refrigerant gas may vibrate the drive shaft 108 particularly when passing through the discharged gas passage 108f. 
Depending on operating conditions of the scroll compressor, further, the natural frequency of the drive shaft 108 may resonate with the vibration frequency of the pulsation to make noise.
The present invention has been proposed in order to solve the aforementioned problems, and an object thereof is to provide a scroll compressor suppressing vibration or noise by suppressing pulsation of discharged gas.
A scroll compressor according to the present invention comprises a first scroll, a second scroll, a discharge port, a pressure chamber and a port. The first scroll has a first spiral body projecting from an end plate. The second scroll has a second spiral body projecting from an end plate for fitting with the first spiral body and forming a compression chamber. The discharge port is provided on the end plate of one of the first and second scrolls. The pressure chamber is provided on the back surface of the other one of the first and second scrolls. The port is provided on the end plate of the other scroll to communicate with the pressure chamber.
This scroll compressor, suppressing pulsation of a fluid compressed in the compression chamber by introducing the fluid into the pressure chamber, can suppress vibration or noise following such pulsation.
Preferably, the pressure chamber is formed by the other scroll and a lid.
In this case, it is possible to prevent pulsation of the fluid flowing into the pressure chamber from directly influencing a casing of the scroll compressor.
Preferably, the scroll compressor further comprises a relief port provided on the end plate of the other scroll for guiding a fluid in the process of compression to the pressure chamber and a relief valve opening/closing the relief port.
In this case, the relief valve is open when the pressure of the fluid in the compression chamber in the process of compression exceeds the pressure in the pressure chamber for feeding the fluid from the compression chamber in the process of compression into the pressure chamber, so that the pressure of the compression chamber in the process of compression is not increased beyond the pressure in the pressure chamber but over-compression is suppressed while the difference between the pressure of the compression chamber immediately before communicating with the discharge port and a discharge pressure is reduced and pulsation of the discharged fluid can be more suppressed when the compression chamber communicates with the discharge port. The timing for feeding the fluid into the pressure chamber through the relief valve deviates from the timing for discharging the fluid from the discharge port, thereby leveling the pressure of the fluid and reducing pulsation thereof.
More preferably, the discharge port communicates with a passage provided in a drive shaft for driving the first scroll or the second scroll.
In this case, vibration of the drive shaft or the like can be effectively suppressed in the so-called in-shaft discharge type scroll compressor having a drive shaft formed with a passage for passing a fluid therethrough.
Preferably, the first scroll is a fixed scroll, the second scroll is a movable scroll, and the port is provided on the fixed scroll.
In this case, the pressure chamber and the port communicating with the pressure chamber are formed on the side of the fixed scroll, whereby the pressure chamber and the port can be more readily formed as compared with the case of forming the same on the side of the movable scroll.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.